Question: Which company {manages} {Boeing 707} for which the {holding company} is {United Continental Holdings}?
Paraphrase: Which company {oversees} {Boeing 707} for which the {holding company} is {Joined together Mainland Holdings}?
SPARQL (Wikidata): SELECT ?answer WHERE { wd:Q6394 wdt:P137 ?answer . ?answer wdt:P749 wd:Q871700}
Answer: Continental Airlines